Mayor-elect Bill de Blasio will appoint former top schools official Carmen Farina as the city’s next chancellor on Monday, a source told the Post on Sunday.

De Blasio will make the announcement at William Alexander Middle School 51 in Park Slope, which both of his children attended, the source said.

The Post reported on Dec. 18 that the mayor-elect had been courting the 71-year-old Farina, a former deputy chancellor, and that she said she was ready to take the job.

“Ms. Farina has immense accumulated wisdom having worked in the NYC public school system recently and through some of its darkest days in the 1980s and ‘90s,” a former principal with knowledge of the selection process said Sunday night.

“I hope that she will move our schools forward from the Bloomberg era instead of backward to the chaotic, unaccountable, patronage-driven system it was before mayoral control,” he said.

Farina has four decades of experience and has been nearly universally lauded as a serious educator — even by those who are critical of de Blasio’s views on the school system.

She has been a longtime adviser to the mayor-elect on education issues and has a vast knowledge of the city’s enormous school system.

Current Chancellor Dennis Walcott said he is stepping down on Dec. 31 as de Blasio prepares to be sworn in to office.

Farina emerged as the chancellor not only because of her ideological mesh with de Blasio, but also because many of the leading candidates had political or ideological strikes against them.

Farina was a teacher at PS 29 in Brooklyn before being named principal of PS 6 on Manhattan’s Upper East Side in 1991.

Ten years later, she was named superintendent of District 15 in Brooklyn.

She became regional superintendent, then deputy chancellor from 2004-2006.

Meanwhile, a group of parents and politicians is suing to block Mayor Bloomberg’s planned extensive of the charter school system.

The lawsuit filed jointly in Manhattan Supreme Court by Mark-Viverito, Public Advocate-elect Letitia James and other activists — seeks to halt the placement, or “co-location,” of 42 charter schools in public-school facilities.

The Bloomberg administration said in October it had approved the schools.